The purpose of this project is to continue specific analyses of the Collaborative Home Infant Monitoring Evaluation (CHIME) Study, to continue to conduct the National Infant Sleep Position (NISP) Study, and to serve as a resource for public use datasets from CHIME and NISP, which were developed during the previous grant award period. The CHIME Study enrolled almost 1,100 infants at five university-based clinical sites. The CHIME dataset includes raw and analyzed physiological waveforms from 900,000 hours (300GB) of home monitoring records; 700 overnight polysomnograms; 21,000 cardiorespiratory events exceeding recording thresholds; 6,000 events exceeding conventional alarm thresholds; and 600 events exceeding extreme thresholds. In particular, the proposed analyses of the CHIME data will assess the factors and physiological processes that predict extreme cardiorespiratory events to include early antecedents, developmental patterns, and immediate characteristics of onset and recovery. The NISP Study, begun in 1992, is an annual telephone survey of nighttime caregivers of infants less than eight months of age in the 48 coterminous states to assess infant care practices and dissemination of the AAP recommendation regarding infant sleep position. Continuation of the NISP Study will evaluate trends in infant sleep practices and dissemination of the "Back to Sleep" recommendation, and the factors that influence these trends. Efforts will be made to increase the proportion of minorities in the completed calls, while using the current list sample. Furthermore, the investigators will complement the NISP survey with alternative methodologies designed to illuminate risk factors for non-compliance in minority groups. Finally, an infrastructure will be put in place to facilitate public access to both the CHIME and NISP datasets. The public access service will include: (1) maintaining a website that provide information on the available data and how to obtain it; (2) processing queries regarding the data and maintaining a database that tracks the progress of the requests; (3) providing consultation on the data needed to facilitate the delivery, i.e., all or part of the database; (4) providing the data in CD ROM format with appropriate documentation for use of the data; (5) and providing fee-for-service consultation on the use of the database beyond the baseline support.